3214 BROADWAY BROADWAY KINECT APARTMENTS 2021-08-11

• • CITY OF EVERETT STORMWATER MANAGEMENT MANUAL • f. Level spreaders • g. Berms. Design and Installation Specifications • 1. Made of urethane foam sewn into a woven geosynthetic fabric. • 2. It is triangular, 10 inches to 14 inches high in the center,with a 20-inch to 28-inch base. A 2—foot • apron extends beyond both sides of the triangle along its standard section of 7 feet. A sleeve at one end allows attachment of additional sections as needed. • 3. Install with ends curved up to prevent water from flowing around the ends. 4. The fabric flaps and check dam units are attached to the ground with wire staples. Wire staples • should be No. 11 gauge wire and should be 200 millimeters to 300 millimeters in length. • 5. When multiple units are installed,the sleeve of fabric at the end of the unit shall overlap the • abutting unit and be stapled. • 6. Check dams should be located and installed as soon as construction will allow. • 7. Check dams should be placed perpendicular to the flow of water. • 8. When used as check dams,the leading edge must be secured with rocks, sandbags, or a small key • slot and staples. • 9. In the case of grass-lined ditches and swales,check dams and accumulated sediment shall be removed when the grass has matured sufficiently to protect the ditch or swale unless the slope of the swale is greater than 4 percent. The area beneath the check dams shall be seeded and • mulched immediately after dam removal. • Maintenance Standards • 1. Triangular silt dams shall be monitored for performance and sediment accumulation during and • after each runoff producing rainfall. Sediment shall be removed when it reaches one half the height of the dam. • 2. Anticipate submergence and deposition above the triangular silt dam and erosion from high flows • around the edges of the dam. Immediately repair any damage or any undercutting of the dam. lb 3.3.10 BMP C209: Outlet Protection • • Purpose • Outlet protection prevents scour at conveyance outlets and minimizes the potential for downstream erosion by reducing the velocity of concentrated stormwater flows. IP Conditions of Use Outlet protection is required at the outlets of all ponds,pipes, ditches, or other conveyances, and where ID runoff is conveyed to a natural or manmade drainage feature such as a stream,wetland,lake, or ditch. • Design and Installation Specifications • See Volume I,Chapter 6.6. Maintenance Standards • 1. Inspect and repair as needed • 2. Add rock as needed to maintain the intended function • • • Volume II— Construction Stormwater Pollution Prevention 3-48 • •